In recent years, LED modules (light-emitting modules) formed by mounting a semiconductor light-emitting element such as an LED (light-emitting Diode) chip on a mounting substrate have been used for various illumination devices (lamps). Such LED lamps using the LED module require a configuration for efficiently extracting light from the semiconductor light-emitting element to the outside of the lamps. For example, PTLs 1 and 2 describe such techniques for improving the light extraction efficiency (luminous efficiency).
PTL 1 adopts a configuration in which no light-shielding object such as an electrode and a bonding wire exists in a light-emitting direction of light from the semiconductor light-emitting element.
PTL 2 adopts a configuration in which light from a semiconductor light-emitting element is transmitted into a mounting substrate without being reflected by a surface of the mounting substrate as little as possible.
PTL 3 discloses a light-emitting element mounting substrate in which an aluminum plate is bonded to a back surface of a ceramic substrate on the opposite side to an LED chip mounting surface. The light-emitting element mounting substrate thus configured can reflect light from an LED chip, which transmits through the ceramic substrate, on the aluminum plate bonded to the back surface of the ceramic substrate.